Bumper unit for cranes



May 10, 1955 R. G. LE TOURNEAU BUMPER UNIT FOR CRANES Original Filed Aug. 23, 1948 mvgnrron Rabi GLeTburneau ATTORN EYS United States Patent BUMPER UNIT FOR CRANES Robert G. Le Tourneau, Longview, Tex., assignor to R. G. Le Tourneau, Inc., Stockton, Calif., a corporation of California Original application August 23, 1948, Serial No. 45,726. Divided and this application February 1, 1952, Serial No. 269,427

1 Claim. (Cl. 2128) This invention is directed to an improvement in a wheeled or portable crane of the type which includes an upstanding elevator frame mounted for forward tilting movement, and a boom-supporting elevator carriage mounted for vertical movement on the elevator frame; the present application being a division of my copending application Serial No. 45,726 filed August 23, 1948, now Patent No. 2,589,102.

The major object of this invention is to provide the crane with a novel cushion bumper mounted in position for engagement by the elevator frame upon forward tilting thereof; the bumper serving to limit and cushion such forward tilting movement of the elevator frame.

It is also an object of the invention to provide a bumper unit for cranes which is designed for ease and economy of manufacture.

Still another object of the invention is to provide a practical and reliable bumper unit for cranes, and one which will be exceedingly effective for the purpose for which it is designed.

These objects are accomplished by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claim.

In the drawings:

Fig. 1 is a side elevation of a wheeled crane embodying the present invention, and showing the bumper-engaged position of the elevator frame of the crane in dotted lines.

Fig. 2 is an enlarged fragmentary elevation, mainly in section, of the bumper unit.

Referring now more particularly to the characters of reference on the drawings, the invention is embodied in a crane which includes a rigid longitudinally extending body 1 connected, at its forward end, to a tractor 2 by means of a power steering and coupling unit, indicated generally at 3.

The body 1 is supported, at its rear end, by means of rear wheels 4.

An elevator frame 5 upstands from the rear end of the crane and is pivotally mounted for tilting movement in a longitudinal vertical plane; the forward limit of such tilting movement of the elevator frame 5 being indicated in dotted lines in Fig. 1.

Tilting of the elevator frame 5, i. e. its swinging adjustment in a longitudinal vertical plane, is accomplished by means of a cable operated, tilt control assembly 6 connected between said frame 5 and an upstanding A-frame 7 on the body 1. The tilt control assembly 6 is actuated by a Winch 8.

The elevator frame 5 is fitted therein with a roller mounted elevator carriage 9, and a boom 10 is fixed in tor carriage. The boom 10 supports a hoist cable 11 operated by a winch 12.

The elevator carriage 9 is vertically adjusted by a control cable system 13 which includes a winch 14.

When the elevator frame 5 is tilted forwardly by the tilt controlassembly 6, such motion is limited to a maxi mum extent predetermined by a bumper unit 15. A cross bar 16 is mounted on the A-frame 7, and is fitted with one or more of the bumper units 15 positioned for engagement with parts of the elevator frame 5 as the latter tilts forwardly. Each such bumper unit 15 is constructed as follows:

A fixed sieeve 17 is rigidly mounted on the cross bar 16 and extends at a rearward and upward incline, and a movable sleeve 18 partially telescopes the fixed sleeve 17 from the free end of the latter. A heavy-duty compression spring 19 is disposed in the sleeve assembly and bears, at the inner end, against a base plate 20 mounted in the fixed sleeve 17 by means including an internal sleeve 21. At its outer end the spring 19 bears against a pad 22 on the outer or free end of the movable sleeve 18. The movable sleeve 18 is held against escape from the fixed sleeve 17 by a bolt 23 secured to sleeve 17 and projecting through a longitudinal slot 24 in sleeve 18. This permits the movable sleeve to work inwardly against the spring 19 within the limits of the slot 24, but said bolt 23, normally in the inner end of slot 24, prevents the movable sleeve 18 from escaping under the action of spring 19.

From the foregoing description it will be readily seen that there has been produced such a device as substantially fulfills the objects of the invention, as set forth herein.

While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claim.

Having thus described the invention, the following is claimed as new and useful, and upon which Letters Patent are desired:

A bumper unit for the forwardly tiltable elevator frame of a crane, said unit comprising, with a cross bar on the crane ahead of said frame, a sleeve fixed on and pro-.

jecting rearwardly from one face of said bar, a movable sleeve in telescopic relation with and projecting rearwardly from the fixed sleeve, a pad fixed on the rear end of the movable sleeve for engagement with the elevator frame, a relatively short sleeve projecting rearwardly from said face of the cross bar inside the fixed sleeve, a cross plate supported by the inner end of said short sleeve, and a compression spring between and engaging said pad and plate.

References Cited in the file of this patent UNITED STATES PATENTS 1,106,558 Halladay Aug. 11, 1914 1,628,826 Covalence May 17, 1927 1,658,873 Younkman Feb. 14, 1928 2,394,314 Le Tourneau Feb. 5, 1946 2,438,660 Garner Mar. 30, 1948 2,444,835 Le Tourneau July 6, 1948 2,495,138 Royle Jan. 17, 1950 2,509,686 Huston May 30, 1950 

